With the growing safety awareness of consumers, there is increasing demand for safer detergents. In particular, infants may accidentally swallow a detergent or lick a surfactant remaining on fingers. Thus, there is a demand for detergents containing a food additive surfactant, which is safe even in the case of accidental ingestion and has disinfection and cleaning effects.
“Guidelines for Measures against Novel Influenza (Feb. 17, 2009)” drawn up by the Ministry of Health, Labour and Welfare of Japan in response to a recent pandemic of novel influenza suggests the importance of “hand-washing” as an effective infection preventive measure. A hand-washing method generally involves washing hands, for example, with soap suds. It is desirable to use safe detergent components in such hand soaps for infants and children.
For example, polyglycerin fatty acid ester and sucrose fatty acid ester surfactants are food additives, but these surfactants have poor foaming characteristics, and use of such surfactants as detergent components may result in insufficient hand-washing. Thus, there is a demand for detergents that contain a food additive surfactant as a main component and have satisfactory foaming characteristics. Another infection preventive measure other than hand-washing may be a method for spraying and rubbing hands with an antiseptic solution, such as an alcohol preparation. Recently, for infants, who cannot rub their hands evenly with sprayed antiseptic solution, an antiseptic foam that can entirely cover their hands for disinfection has been commercially available. However, use of such a food additive surfactant as a detergent component may result in not only poor foaming but also precipitation during cold storage because of poor compatibility of a polyglycerin fatty acid ester or a sucrose fatty acid ester with an alcohol. Thus, there is a demand for an antiseptic foam that can entirely cover hands with abundant foam even in the presence of a large amount of alcohol and has good low-temperature stability.
Polyoxyethylene sorbitan fatty acid esters are surfactants that were designated as food additives in Japan in April, 2008. Polyoxyethylene sorbitan fatty acid esters are less irritating to the human body and are compatible with solvents, such as water and alcohols. Thus, attempts are being made to use polyoxyethylene sorbitan fatty acid esters in applications that require a high degree of safety, such as washing of vegetables and infant feeding bottles, as well as food applications.
Detergents that contain polyoxyethylene sorbitan fatty acid esters are described in Patent Literatures 1 and 2, for example. Patent Literature 1 proposes a disinfectant detergent composition for toilet seats containing one or more nonionic surfactants. The disinfectant detergent composition contains (A) a lower alcohol, (B) an organic acid and an alkali metal salt thereof, or an inorganic acid and an alkali metal salt thereof, and (C) a polyoxyethylene sorbitan fatty acid ester. This detergent composition has improved low-temperature storage stability and excellent disinfection effects but does not have satisfactory foaming characteristics.
Patent Literature 2 proposes a detergent for food that contains (A) a polyoxyethylene sorbitan fatty acid monoester and (B) a lipophilic polyhydric alcohol fatty acid monoester having HLB of 8 or less. This detergent for food washes well but does not have satisfactory foaming characteristics.
Furthermore, the lipophilic polyhydric alcohol fatty acid monoester may be precipitated during cold storage, resulting in low storage stability.
Thus, no disinfectant detergent is available that contains a food or a food additive as a main detergent component and has satisfactory foaming characteristics, excellent disinfection effects, and excellent low-temperature stability.